Torque Converter Stall Test

TORQUE CONVERTER STALL TEST

This test measures the maximum engine speed at the time the torque converter stalls with the selector lever in the "D" or "R" position. With this test, the holding abilities of the clutch and brake that are incorporated in the transaxle can be checked.

WARNING:
For safety, operators must not stand in front of and at the rear of the vehicle during this test.

1. Check the transmission fluid level, transmission fluid temperature, and engine coolant temperature.

- Transmission fluid level: In the "HOT" mark on the dipstick

- Transmission fluid temperature: 70 - 80°C (158 - 176°F)

- Engine coolant temperature: 80 - 100°C (176 - 212°F)

NOTE:
Use M.U.T.-III. to measure the transmission fluid temperature.

2. Raise the vehicle.

3. Pull the parking brake lever, and then fully depress the brake pedal.

4. Start the engine.

5.
CAUTION:

- Do not maintain the WOT condition for 5 seconds or longer.

- When continuing the stall test, make sure that the fluid temperature does not exceed 80°C (176°F). If the transmission fluid temperature exceeds 80°C
(176°F), run the engine at around 1,000 r/min for 1 minute or longer to lower the transmission fluid temperature to 80°C (176°F) or less.

Move the selector lever to the "D" range and fully depress the accelerator pedal. Quickly read the maximum engine speed at this time.
Standard value - Stall speed: 2,400 - 2,900 r/min


6. Move the selector lever to the "R" range, and then repeat the previous step.
Standard value - Stall speed: 2,400 - 2,900 r/min


JUDGEMENT OF TORQUE CONVERTER STALL TEST RESULTS

1. Stall speed is high when selector lever is in both
"D" and "R" ranges.

- Malfunction of the torque converter (Torque converter and input shaft spline are slipping)

- Malfunction of the valve body

- Damaged wiring harness and connectors

- Malfunction of TCM

2. Stall speed is high only when selector lever is in the "D" range.

- Forward clutch is slipping

3. Stall speed is high only when the selector lever is in the "R" range.

- Reverse brake is slipping

4. Stall speed is low when selector lever is in both "D" and "R" ranges.

- Malfunction of the torque converter

- Line pressure is low

- Low engine power